56 PHYSIOGRAPHY AND GEOLOGY OF THE COASTAL PLAIN PROVINCE. 



Coastal Plain of Virginia and probably the highest in the entire Atlantic 

 Coastal Plain province. Although somewhat lower the cliffs at Carters 

 Wharf on the Eappahannock Eiver, at Mt. Folly and Yorktown on the 

 York River, at Drewrys Bluff, Howlett House and Kings Mill on the James 

 Eiver, and at Point of Eocks on the Appomattox Eiver are equally 

 picturesque. 



Minor streams. — Entering the head of almost every estuary and flowing 

 into them from the side are tributary streams of varying lengths which have 

 not yet cut down to tide and which have sufficient fall to furnish considerable 

 water power. Hundreds of these, all through the region, have been dammed 

 and used to generate the motive power for grist and saw mills. Not infre- 

 quently these streams have very deep, steep-sided valleys and where they 

 are numerous the country is decidedly rugged. On the Potomac Eiver side 

 of King George County there is such a region. 



A marked peculiarity is noticeable in the relative lengths of these 

 minor streams draining opposite sides of the peninsulas. On the Northern 

 Neck, the region between the Potomac and Eappahannock rivers, the divide 

 lies very close to the Potomac Eiver and as a result the streams flowing into 

 the Potomac are short, swift streams with precipitous valleys, while those 

 flowing into the Eappahannock are longer, descend from the upland in 

 easier stages, and have more open valleys. The same features are observed 

 in the peninsulas between the Eappahannock and York rivers and between 

 the York and James rivers, while more than three-fourths of the region 

 lying to the south of the James Eiver is drained southward iniu the Chowan 

 Eiver of North Carolina. The unsymmetrical location of the divides snows 

 that the southward-flowing streams with their greater drainage areas liave 

 been enabled to cut back into the divides more rapidly than have the streams 

 flowing to the north. This condition of affairs has probably been brought 

 about by a slight tilting of the whole region to the souihward or south- 

 westward although an attempt has been made to find an explanation foi 

 this phenomenon from the effects of the earth's rotation. 



The Dismal Swamp. — A discussion of the drainage of Coastal Plain 

 Virginia should include a description of the Dismal Swamp. The state- 

 ment which follows is taken from the Norfolk folio, U. S. Geological 

 Survey, by N. H. Darton, who has made an exhaustive study of the district. 



"The larger portion of this great fresh-water morass lies in the Norfolk 

 quadrangle. It is an area of moderatelv elevated, nearly level land with 

 such imperfect drainage that it remains constantly inundated to a slight 

 depth. The outlines of the swamp area are irregular and usually the limits 



